Is Sentinel’s Metal Gear Sahelanthropus a bit too expensive for you? Maybe the model kit by Kotobukiya is a good alternative. While the price hasn’t been detailed yet, these are often much cheaper since they are kits you have to put together and paint yourself.
It also comes with three figures: Eli (inside the cockpit), Skull Face, The Third Boy and Snake. When it’s upright the height is 200 mm.